The majority of CNS compounds dropped from clinical trials are abandoned due to an inability to demonstrate efficacy ill the target patient population These failures are often linked to the selection of in appropriate doses for investigation. This often necessitates the design and initiation of additional studies, resulting in significant delays and increased development costs. MIICRO's patented OMEI method uses FDG PET to determine the cerebral metabolic effects of drugs in humans. MIICRO uses its OMEI PET services to tell client pharmaceutical developers, in quantitative terms, whether a compound affects the brain, where it affects the brain, and how one drug compares to another. In Phase I of this project, we demonstrated that OMEI PET can characterize the dose-relate biological effects of a drug in the human brain and can establish the duration of tissue effects. We propose to extend our research and to develop a unique new service, the Optimum Dose Evaluation (ODE). When applied in early clinical tria1s, the ODE will help select appropriate dose ranges for subsequent clinical' trials. The ODE will thereby optimize the design of definitive-clinical trials, thus limiting the associated risk of failure and avoiding the expense of unnecessary trial arms. PROPOSED COMMERCIAL APPLICATION: Despite the fact that the development of CNS drugs is the largest and fastest-growing segment for pharmaceutical innovation and development, CNS drugs take longer, cost more, and are plagued with more failed trials than non-CNS drugs in development. A quantitative, cost-effective, new tool for evaluating drug doses will have a significant effect on the time and cost of CNS drug development, and will help avert failed trials due to inadequate data or poor study design.